The present invention is concerned with a housing designed for containing and enclosing a dental amalgamator used in dental offices. The housing is adapted to retain liquid mercury which is inevitably lost during operation of the amalgamator such that the liquid mercury may be recovered. The housing is also adapted to confine mercury vapor generated during operation of the amalgamator and to exhaust the mercury vapor to avoid contamination of the atmosphere of the room or dental office in which the amalgamator is located.
In recent years the dental profession and those concerned with occupational safety have become increasingly aware and concerned with the problem of mercury contamination in dental offices. The dental profession is one of the large consumers of mercury metal which is used in amalgams containing mercury, silver and other optional metals to fill cavities in teeth. Though the amalgams are soft at first, they form hard, lasting fillings. The amalgams are commonly produced in dental offices by placing the mercury, silver and optional other metals in a mortar or capsule which usually also contains a small pestle or pellet. The mortar is secured in an electrically driven agitating device or amalgamator which causes the pestle to be oscillated within the mortar providing an effective triturating or grinding action to form the amalgam. U.S. Pat. Nos. 2,201,428; 2,286,599 and 2,286,600, all to E. L. Chott and incorporated by reference in the present disclosure, describe in detail various mortar and pestle designs and dental amalgamators.
Mercury toxication is frequently encountered by dentists and other personnel who regularly inhabit dental offices and prepare amalgams for use in filling teeth. The mercury toxication is from two sources, namely, direct absorption of liquid mercury into the body through contact or handling of mercury and mercury containing compounds and through inhalation of vapor emitted during the amalgamation process when mercury and mercury-containing substances are volatilized. The problems of mercury toxication in dental offices are described in detail in the Journal of The American Dental Association, Vol. 92, No. 6, (1976) in two articles entitled "Mercury Toxicity in the Dental Office: A Neglected Problem" by Manteyla et al. (pages 1189-1194) and "The Silent Hazard: An Unusual Case of Mercury Contamination of a Dental Suite" by Pagnotto et al. (pages 1195-1198). These articles are incorporated by reference in the present disclosure.
Liquid mercury frequently escapes from the mortar during the amalgamation process, contaminating work benches, rubs, equipment, etc. This lost liquid mercury becomes a potentially hazardous source of mercury vapor when it vaporizes into the atmosphere. Also as mentioned previously mercury vapor is evolved during amalgamation, further contaminating the atmosphere of the dental office.
Mercury contamination is hazardous to the health of those persons who are exposed to the liquid mercury and mercury vapor over an extended period of time. Symptoms of mercury toxication include erthism (a psychic disturbance), tremor, speech disorders, alteration of handwriting, motor and sensory nerve disorders, eye affections, oral pathosis, etc. Safety experts are generally agreed that the mercury vapor content of the ambient air must not be in excess of the threshold limit value of 0.05 mg/m.sup.3.
Dentists and other dental personnel have been cautioned to avoid direct contact with mercury metal and spilling of mercury metal which may contaminate the ambient air due to vaporization. Construction of exhaust systems in dental offices to prevent recirculation of mercury vapor has been recommended. These precautions however, have not been completely effective in maintaining the ambient air mercury vapor level below the threshold limit value of 0.05 mg/m.sup.3.
An object of the present invention is to reduce the risk of exposure of both liquid mercury and mercury vapor in dental offices.
A further object of the invention is to provide apparatus for isolating liquid mercury and mercury vapor from the ambient air in the dental office during operation of dental amalgamators.